yes, I think so too, to prevent releasing games with HDD or USB access which could be used as vulnerability/exploit.
It's certainly possible to write to another path (even just the DLC folder) but would require write access. instead of using /vol/aoc/ they could use the full path instead.
I went to the shop today again, they still didn't receive any copy
that's really not well played by nintendo to not print enough copy for games they know will have lot of demands. do they expect all users to buy the eShop version ?
Edit: Mario_Tennis_Ultra_Smash_READNFO_USA-WiiU-PACT just released, but no Xeno dump yet